Mechanical Engineering Design is the first edition of a largest old preocupation of the authors in this field. It presents the design of the Otto Motors, kinematics and dynamics, a new Otto engine, the efficiency of the engines with internal combustion, the design of the V engines, the design of the distribution mechanisms, the design of the power train and the design of the drivetrain. It presents as well the design of the planetary trains with their real efficiency. The book has 14 chapters. Since the predominant component in all chapters is the dynamics, the book might be called and dynamic design in mechanical engineering. The first chapter presents an original method to determine the efficiency of the gear, the forces of the gearing, the velocities and the powers. Synthesis of classical planetary mechanisms is usually based on kinematic relations, considering in especially the transmission ratio input-output achieved. The planetary mechanisms are less synthesized based by their mechanical efficiency developed in operation, although this criterion is part of the real dynamics of mechanisms, (see the fourth chapter).